This invention relates in general to electrical grounding clamps and, in particular, to an improved ground clamp for providing an electrical grounding coupling for use with a pipe, conduit or ground rods of various diameters, which may have a rusted, painted or dirty surface. More specifically, but without restriction to the particular embodiment and/or use which is shown and described for purposes of illustration, this invention relates to a ground clamp adapted to accommodate such things as grounding conductors, water service pipes, electrical service conduits, and ground rods having diameters ranging from as small as 1/2" to as large as 31/2"; and especially for such conductors which have an oxide coating or are paint covered on their exterior surface.
As is known to those skilled in the art, ground clamps are utilized to provide an electrical ground for pipes and conduits, for example, to dissipate static electricity or whenever it is necessary to protect the safety of persons who might come into contact with such instrumentalities. In effecting such grounding, generally a solid copper wire of preferably AWG sizes 6 through 12 inclusive, is appropriately terminated to ground and then connected to the pipe or conduit by a clamp to effect grounding. However, the coupling of the terminated ground wire to the pipe or conduit to be grounded must be done in a proper manner to ensure an effective electrical connection between the pipe or conduit and the terminated ground wire. This coupling or connection must be maintained at all times free from corrosion and mechanical failure, both at the connection with the terminated ground wire, and at the connection to the rod, pipe or conduit.
When a pipe or conduit that is to be ground is covered with paint, rust or some such thin layer of insulating material over the base metal, procedures must be utilized for cleaning the pipe or conduit surface in order to ensure a suitable grounding. While these surface preparation procedures, scaping or sanding the pipe or conduit, are effective in assuring a properly conditioned surface for grounding, these procedures are also time consuming and, on occasions, may be improperly utilized or not used at all. The present invention provides a structure which is effective to ensure a proper contact with the base metal of the pipe or conduit to be grounded, even if the base surface has not been properly scraped or sanded. The present clamp incorporates many features of the inventor's prior invention disclosed and claimed in George J. Franks, Jr., U.S. Pat. No. 4,626,051, the disclosure of which is incorporated herein by reference.